Self-adhering fastening filament

ABSTRACT

A self-adhering fastening device for releasably adhering an opposing article utilizes an elongated filament having a plurality of integral, generally lateral projections defining fastening elements. The filament is initially formed as an elongated body, which may be in the form of a ribbon, having plurality of slits cut along the longitudinal sides of the body, which slits are subsequently opened up to form spaced fastening elements along the length of the body. The slits may be opened by stretching or twisting the body or by applying heat or chemical treatment to the slitted body.

1 States I i191 ruimlilr Sept. 10, 1974 SELF-ADHERING FASTENING FILAMENT [76] Inventor: George C. Brumlilr, 154 Upper Mountain Ave., Montclair, NJ. 07042 [63] Continuation'of Ser. No. 856,964, Sept. 11, 1969,

abandoned. I

[52] US. Cl. 24/204, 24/87 R [51] Int. Cl. A44b 11/25, A44b 17/00 [58] Field of Search... 24/201 R, 204, 87 R, 30.5 T; 161/21, 48; 139/391 [56] References Cited UNITED STATES PATENTS 3,044,201 7/1962 Lalick 24/204 X 3,123,077 3/1964 Alcamo 24/204 UX 3,290,854 12/1966 MacMurray 24/30.5 T X 3,426,393 2/1969 Mead 24/30.5 T 3,522,637 8/1970 Brumlik 24/204 FOREIGN PATENTS OR APPLICATIONS 975,538 11/1964 Great Britain 24/87 R Primary ExaminerDonald A. Griffin Attorney, Agent, or Firm-Edward F. Levy [57] ABSTRACT A self-adhering fastening device for releasably adhering an opposing article utilizes an elongated filament having a plurality of integral, generally lateral projections defining fastening elements. The filament is initially formed as an elongated body, which may be in the form of a ribbon, having plurality of slits cut along the longitudinal sides of the body, which slits are subsequently opened up to form spaced fastening elements along the length of the body. The slits may be opened by stretching or twisting the body or by applying heat or chemical treatment to the slitted body.

16 Claims, 12 Drawing Figures SELF-ADIIIERING FASTENING FIL Ell N BACKGROUND OF THE INVENTION Various self-gripping fasteners, particularly suitable for releasably fastening fabrics and the like are presently available. Typical of such fasteners is a selfgripping fastener assembly presently marketed under the trademark Velcro which is in the form of pairs of fabric strips which are suitably secured to the opposing fabrics to be fastened together. The Velcro" fastener comprises multiple rows of small verticallyextending open plastic loops secured to the outer surface of one of the matching strips while matching small plastic hooks are secured to the outer surface of the opposite strips. Thus, when the two opposing strips are press-contacted the hooks link with the opposing loops in an interlocking action, and when pulled apart with sufficient force, the hooks disengage from their corresponding loops.

While such conventional fastening assemblies pro vide convenient and effective gripping action, they are subject to the disadvantage of being relatively expensive since the formation of the loops and hooks and the mounting thereof on the fabric strips involves costly manufacturing operations. Further, the Velcro type grip inherently requires that both of the opposing surfaces be provided with matching strips in order toeffect an interlocking grip. 1

It is, therefore, an object of the present invention to provide a fastener device which is integrally made as part of a thread or filament which is then employed either in filament form or in yarn form to form a fabric, felted surface or the like, the latter being self-adhering.

A further object is to provide a novel and improved method of making a self-adhering fastening element which involves an inexpensive manufacturing operation and which is adaptable to present day mass techniques.

Another object of the present invention is to provide a fastening device of the character described in which fabric or felted surfaces formed by the device may be attached to opposed surfaces by the simple application of pressure thereon and may be released'by pulling the surfaces apart with sufficient force.

Additional objects and advantages of the invention will become apparent during the course of the following specification when taken in connection with the accompanying drawings.

SUMMARY OF THE INVENTION A self-adhering fastening device for releasably gripping an opposing article utilizes an elongated filament having a plurality of integral, generally lateral projections defining fastening elements. The filament is ini-' tially formed as an elongated body which may be in the form of a ribbon of constant rectangular cross-section as in the case of the illustrated embodiment. A plurality of slits are cut along one longitudinal side or both sides of the body and these slits are subsequently opened up toform spaced fastening elements along the length of the body. The slits may be opened by stretching or twisting the body or by applying heat or chemical treatment to the slitted body.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a filament having a plurality of diagonal slits or cuts along the edges thereof arranged in a manner to produce a plurality of integral fastening elements according to one embodiment of the invention;

FIG. 1A is a perspective view of the filament in FIG. I after the filament has been elongated to produce integral fastening elements thereon;

FIG. 1B is a perspective view of the filament in FIG. 1 after the filament has been twisted to distribute the integral fastening elements about the periphery thereof;

FIG. 2 is a perspective view of a filament according to an alternate embodiment wherein the filament has a plurality of transverse slits or cuts arranged to produce a plurality of integral fastening elements;

FIG. 2A is a perspective view of the filament in FIG.

- 2 after the filament has been elongated to produce integral fastening elements thereon;

FIG. 3 is a perspective view of a filament having a plurality of inverted, V-shaped slits arranged to produce another type of fastening unit;

FIG. 3A is a perspective view of the filament in FIG. 3 after the filament has been stretched to produce fastening elements thereon;

FIG. 4 is a perspective view of a filament having a plurality of arcuate slits or cuts and a plurality of notches arranged to produce yet another alternate fastening unit;

FIG. 4A is a perspective view of the filament in FIG. 4, after the filament has been elongated to produce fastening elements thereon;

FIG. 5 is an enlarged perspective view of a filament similar to that of FIG. 4A, but made in the form of lamination of two sheets having different coefficients of ex pansion;

FIG. 6 is a perspective view of the filament of FIG. 4A after the filament has been twisted to distribute the fastening elements about the periphery thereof; and

FIG. 7 is a perspective view of a portion of fabric having self-gripping filaments of the present invention mounted thereon.

DETAILED DESCRIPTION barb-like fastening elements 14 as shown in FIG. 1A or to be twisted or otherwise treated to form similar fastening elements 14a as shown in FIG. 1B.

Initially, the filament 10 is in the form of an elongated, flat strip or ribbon of plastic and may be produced by extruding a length of plastic having the desired cross-sectional configuration or by initially extruding an elongated sheet or web of plastic material and subsequently slitting or otherwise cutting the web into a plurality of filaments having the desired size and configuration. The orientation of the molecules in the plastic filaments and the direction of the longitudinal axis of the filaments relative to the molecular orientation may be selected to provide the most desirable properties in the filaments and in the fastening elements, hereafter described, formed on said filaments. For example, in using a plastic material of the type having long linear molecules, the filament may be cut from a plastic sheet or web so that the molecules are generally in line or parallel to the longitudinal axis of the filament to achieve the most favorable physical properties, such as resiliency, tensile strength, and elastic modulus along the longitudinal axis of the filament. The filament may also be initially formed from a laminated sheet or strip of two different or two like plastic materials as will be further described.

Examples of plastic materials from which the filament may be made are: polyolefins, polyvinyls, polyesters, polyamides, cellulose-based polymers, polyurethanes, polyethers, or polysulfones. The filament may also be made from other materials such as elastomers, glass or metal.

After the slits 12 are cut into the longitudinal edges of the plastic filament 10, the latter may be stretched or otherwise elongated by various methods to be described. As the filament 10 is stretched, the central longitudinal portion 16, that is the longitudinal portion between the inner terminating ends of the slits 12, elongates but otherwise remains intact while the longitudinal edge portions separate along the slits 12. The degree or extent of stretching affects the spacing and shape of the fastening elements 14 thus formed, so that the latters characteristics may be varied as desired by controlling the amount of stretching imparted to the filament. In the illustrated embodiment, FIG. 1A, the stretching was such that the plastic material immediately above each cut 12 tended to draw inwardly towards the longitudinal center portion 16 of the filament thereby leaving exposed the plastic material immediately below each cut 12 in the form of triangularlyshaped, barb-like fastening elements 14. The slits 12 on one longitudinal edge of the filament 10 may be staggered relative to those on the opposite longitudinal edge to provide wider distribution of the fastening elements along the length of the filament.

Instead of stretching the filament 10, the latter may be twisted as shown in FIG. 1B. As the filament 10 is twisted, the central longitudinal portion 16, that is the longitudinal portion between the inner terminating ends of the slits 12, remains intact and forms a spiral while the longitudinal edge portions separate along the slits 12. As the separation occurs, the plastic material immediately above each cut tend to twist into spiral form more so than the plastic material immediately therebelow, thereby exposing the latter in the form of projecting barb-like fastening elements 14a which entirely surround the central axis of the filament.

As a further method of forming the fastening elements 14, the slitted filament 10 may be both stretched and twisted.

The stretching may be effected mechanically, for example by utilizing a set of Godet rolls (not shown), or by subjecting the filament 10 to a source of heat, for example steam, or by treating the filament chemically, for example by spraying or dipping the filament with, or exposing the filament to the vapors of, the following solvents: acetone, dimethyl sulfoxide, orthadichloro benzene, phenol, glyoxaldehyde, diphenyl ether, methyl-ethyl keytone, tetramethylene sulfone, tetrahydrofurane, and N,N-dimethylformamide. It will be appreciated that as the stretching is effected by chemical or heat treatment as aforesaid, twisting of the filament may also occur.

Further embodiments of the present invention are shown in FIGS. 2 to 4A to demonstrate, by way of example, that the fastening elements on the filament may be formed in various configurations.

In the embodiment of FIGS. 2 and 2A, a filament 18 is provided with a plurality of slits 20 disposed generally perpendicular to the longitudinal axis of the lilament and extending partially inwardly from both longitudinal edges. Upon stretching of the filament 18, the slits 20 will open up to form generally, laterally disposed fastening elements 22 as shown in FIG. 2A, separated by notch-like spaces 24. The slitted filament 18 may also be twisted, with or without stretching, to facilitate formation of the fastening elements 22 and to distribute the latter about and around the longitudinal axis of the filament.

In a further embodiment as appears in FIGS. 3 and 3A, a filament 26 is provided with a plurality of inverted, V-shaped slits 28 along each longitudinal edge. Upon stretching of the filaments 26, the slits 28 will open up, as shown at 30 in FIG. 3A, to form longitudinally spaced fastening elements 32 having pointed ends 34. Here again, the filament 26 may be twisted, with or without stretching, to facilitate formation of the fastening elements and to distribute and further expose the pointed ends 34 thereof.

The filament 36 shown in the further alternate embodiment of FIGS. 4 and 4A has cuts 38 along its longitudinal edges which are adapted to form hook-like fastening elements 40 upon subsequent stretching. The cuts 38 in the filament 36 are in the form of a plurality of partial circles arranged tangentially to one another along the longitudinal edges of the filament 36. Each circular cut 38 extends out to the longitudinal edge whereby the plastic material along the longitudinal edges between adjacent tangential cuts define small notch-forming pieces 42 which are cut out from the filament 36 and fall away or are otherwise removed from the filament 36 as the cuts 38 are made. Notches 44 are formed along the edges of the filament where the pieces 42 are removed. It will be seen that the cuts 38 do not form a complete circle, and the end 46 of the circular cut 38 deviates from its circular configuration in that it is turned or otherwise directed back on itself generally towards the center of the circular cut. The narrow section of plastic included within the turned back part of the cut 46 defines a hook-forming section 48 as will be described. The cuts 38 are arranged in the configuration shown and described so that upon 4 stretching of the filament, the cuts 36 will open to form hooked fastening elements 40 as shown in FIG. 4A. As the filament 36 is stretched, the tangentially disposed cuts 38 separate and part. As stretching continues and the slits enlarge, the formation of the fastening elements cause the latter to open up to such extent that the plastic material between the cuts tends to uncurl. The aforementioned turned back part 46 of the cut line 38 also separates and parts, and as this occurs the hook-forming sections 48 are also uncurled and carried generally laterally outwardly towards the longitudinal edges of the filament to form hooks, as shown in FIG. 4A. Small segments 50 remain on the filament after stretching where the hook forming section 48 was previously delineated by the turned back out 46. It will be seen that the fastening elements thus formed has a hooked end directed back on itself. This is a desirable feature where greater adhering or gripping action is de sired as will be further described.

As in the case of the prior embodiments, the filaments 36 may also be twisted to dispose and distribute the fastening elements 40 about the longitudinal axis of the filament. The degree to which the hooks 40 are opened may be varied by selective control of the heat, mechanical, or chemical treatment to which the filaments are subjected.

FIG. 6 shows the filament 36 of FIG. 4A in twisted form. When the filament 36 is twisted, as shown, the

central longitudinal portion forms a spiral, and the fastening elements 40are distributed circumferentially around the central axis thereof.

It will be recalled that the filaments may be made from a laminated sheet or strip of two'different or two like plastic materials. In this regard, the properties of the two laminated sheets may be different in order to facilitate formation of the fastening elements. For example, a lamination of two different plastic sheets having different coefficients of expansion or contraction may be utilized so that upon subsequent application of heat or chemical treatment, the filament will tend to twist and the fastening elements will tend to curl or form hooks due to the different expansion rates. The lamination may also consist of two sheets of like plastic wherein one sheet has been treated (eg by exposure to cold air) to change its coefficient of expansion, or its tendency to shrink. Also the direction of orientation of the two laminated sheets may be arranged relative to one another to obtain desired physical characteristics.

FIG. 5 shows, by way of example, a filament which has been cut to form hook-like fastening elements 62 similar to that shown in FIG. 4A. In this instance, the filament 60 is formed of two sheets or layers 64 and 66 of plastic material, the sheet 64 being shrinkable under suitable treatment, which may be mechanical or chemical treatment. When the filament 60 is twisted, it will have substantially the same shape as shown in FIG. 6.

The filaments may be'cut or slit only along one longitudinal edge and then stretched or twisted, or both, as previously described. It is preferable however to cut the filaments along both longitudinal edges as shown, in'

order to increase the gripping efficiency of the filament.

The filaments heretofore described may readily be spun together to form a yarn to be subsequently interwoven or felted together as hereinafter described. Further, the filaments may be co-spun with ordinary fibres to form a yarn in which the filaments are a minor constituent. The filament may be twisted during the spinning operation to effect formation and distribution of the fastening elements about the filament. Also, the slitted filaments l0, 18, 26, 36 may be spun together to form a yarn which thereafter may be subjected to heat or chemical treatmentto effect formation and distribution of the fastening elements. A fabric may be made of interwoven yarns spun from slitted filaments of the present invention and upon completion of manufacture of the fabric, the latter may be subjected to heat or chemical treatment to effect formation and distribution of the fastening means. In some cases it might be desirable to initially stretch the'filament before spinning and subsequently twist the filament during or after spinning. It will be appreciated that the'number of operations and their sequence may be varied as desired in forming the fastening means from the slitted filaments.

Yarns formed from filaments of the present invention may serve various other purposes, for example, a single length of the yarn formed from filaments 36 shown in FIG. 4A, for example, may be woven into regular fabric to provide a zipper-type closure line in the fabric. In addition, a plurality of yarns spun'from filaments of the present invention may be matted together in a felting operation to form a felt fabric. In the felting operation, when the yarns are pressed together, the fastening means will engage continuous yarns to form a skeined array of interlocking yarns.

Where the filaments of the present invention are added as a minor constituent to a large group of regular fibres or threads and co-spun into yarn, the filaments are initially 'in their flat, unexpanded and untwisted form during spinning so that the barbs or hooks are not exposed. After spinning, the yarn itself is treated by heat, chemicals, etc. as previously described, to cause the filaments to stretch, twist, or both stretch and twist to such an extent to form and expose the barbs or books which project from the yarn and provide the desired gripping function. When required, the filaments are not so treated until the yarn has been woven into a fabric, whereupon the entire fabric is treated to expose the barbs or hooks.

The filaments heretofore described may be added to a non-woven fabric as well-as a woven fabric. For example, a relatively small amount of filaments may be added to a mass of fibres before felting. A felt-body is thus produced in which the filaments may, but do not necessarily project to provide a gripping action. If no external gripping action is produced, the filaments serve to improve the cohesion of the felt body by holding together the felted fibres.

FIG. 7 shows a sheet of felted material 70, to the fibres 72 thereof are added a plurality of filaments of the present invention, for example the twisted filaments 36 shown in FIG. 6. The filament fastening elements 40 project from the surface to provide an external gripping action, and some of the fastening elements are located beneath the surface of the sheet 70 to attach the filaments 36 to the sheet and also to hold together the felted fibres. Because of the projecting fastening elements, when the sheet 70 is pressed against the penetrable surface of another sheet or article, the latter adheres to sheet 70.

A fastening fabric formed by felting or weaving the aforesaid yarns may be suitably secured such as by stitching, by its own self-gripping action, or by means of adhesive to one of two articles to be releasably fastened. In some cases, if the material of the other article to be fastened is of a soft or frangible nature, the fastening fabric can be attached thereto by its self-adhering action without requiring additional fastening means. If the material of the other article is smooth or impenetrable by the fastening elements, then the fastening fabric may be suitably secured to such other article so that when the two article surfaces are pressed together, the fastening elements will engage opposing fabric yarns with a self-adhering action.

While preferred embodiments of the invention have been shown and described, it is obvious that numerous ing fastening elements extending along the length of said longitudinal edge.

2. A filament according to claim 1 in which the said incisions are open and the said fastening elements are exposed.

3. A filament according to claim 1 in which said body is twisted into spiral from with said fastening elements distributed circumferentially around the central axis thereof.

4. A filament according to claim 1 in which said incisions extend perpendicularly to the axis of said body.

5. A filament according to claim 1 in which said incisions are inclined at an acute angle to the axis of said body.

6. A filament according to claim 1 in which said incisions define barbs.

7. A filament according to claim 1 in which said incisions define hooks.

8. A filament according to claim 1 wherein said body is formed of at least two layers of plastic materials, at least one of said layers being shrinkable under mechanical, physical, or chemical treatment.

9. A filament according to claim 8 wherein said flat body is made of metal.

10. A filament according to claim 8 wherein said flat body is in the form of an elongated ribbon made of a plastic material having long linear molecules.

11. A filament according to claim 10in which at least a portion of said linear molecules have their longitudinal axes generally aligned with the axis of said body.

12. A filament according to claim 8 wherein said flat body is formed of two layers of plastic materials, one of said layers being shrinkable under mechanical, physical or chemical treatment.

13. A filament according to claim 1 in which each of said projecting fastening elements has its end portion at least partially turned back on itself to form a hook at the end thereof, said body being flat and twisted into spiral form with said projecting fastening elements distributed circumferentially around the central axis thereof.

14. A fibrous material comprising a mass of crossing filaments, at least some of said filaments comprising an elongated body having opposed longitudinal edges, and a plurality of deep transverse incisions extending along the length of at least one of said longitudinal edges and extending inwardly from said edge toward the center of said body, adjacent pairs of said incisions forming a row of laterally-projecting fastening elements extending along the length of said longitudinal edge.

15. A fibrous material according to claim 14 which constitutes a woven fabric.

16. A fibrous material according to claim 14 which constitutes a non-woven fabric. 

1. A fastening filament comprising an elongated flat body having opposed longitudinal edges, and a plurality of deep transverse incisions extending along the length of at least one of said longitudinal edges and extending inwardly from said edge toward the center of said body, said filament being non-reversibly distortable from its normal condition to cause adjacent pairs of said incisions to simultaneously form a row of laterally projecting fastening elements extending along the length of said longitudinal edge.
 2. A filament according to claim 1 in which the said incisions are open and the said fastening elements are exposed.
 3. A filament according to claim 1 in which said body is twisted into spiral from with said fastening elements distributed circumferentially around the central axis thereof.
 4. A filament according to claim 1 in which said incisions extend perpendicularly to the axis of said body.
 5. A filament according to claim 1 in which said incisions are inclined at an acute angle to the axis of said body.
 6. A filament according to claim 1 in which said incisions define barbs.
 7. A filament according to claim 1 in which said incisions define hooks.
 8. A filament according to claim 1 wherein said body is formed of at least two layers of plastic materials, at least one of said layers being shrinkable under mechanical, physical, or chemical treatment.
 9. A filament according to claim 8 wherein said flat body is made of metal.
 10. A filament according to claim 8 wherein said flat body is in the form of an elongated ribbon made of a plastic material having long linear molecules.
 11. A filament according to claim 10 in which at least a portion of said linear molecules have their longitudinal axes generally aligned with the axis of said body.
 12. A filament according to claim 8 wherein said flat body is formed of two layers of plastic materials, one of said layers being shrinkable under mechanical, physical or chemical treatment.
 13. A filament according to claim 1 in which each of said projecting fastening elements has its end portion at least partially turned back on itself to form a hook at the end thereof, said body being flat and twisted into spiral form with said projecting fastening elements distributed circumferentially around the central axis thereof.
 14. A fibrous material comprising a mass of crossing filaments, at least some of said filaments comprising an elongated body having opposed longitudinal edges, and a plurality of deep transverse incisions extending along the length of at least one of said longitudinal edges and extending inwardly from said edge toward the center of said body, adjacent pairs of said incisions forming a row of laterally-projecting fastening elements extending along the length of said longitudinal edge.
 15. A fibrous material according to claim 14 which constitutes a woven fabric.
 16. A fibrous material according to claim 14 which constitutes a non-woven fabric. 